The present invention relates to power switching mechanisms and more particularly relates to a novel mechanical power switching device having dual-mode equipment and personnel protection means in a compact assembly.
It is known to series connect a mechanical power control switch and fuse device to protect a power utilization mechanism and the power lines thereto from the adverse thermal effects of an overcurrent caused by a short circuit therein or a faulty utilization device. This arrangement does not provide protection to personnel against an electrical shock hazard. Recently there has been a significant interest in ground fault protective means to provide such personnel protection. Ground fault protection is applicable to both consumer and light industrial circuits where relatively large and costly circuit breakers having thermal and/or electromechanical overcurrent protection arrangements are not utilized. In circuits where a fuse must suffice for overcurrent protection, it is nevertheless desirable to provide a compact and relatively inexpensive power control unit including ground fault detection means cooperating with the mechanical switch to protect against personnel shock hazards.